NationalSecurityAgency/ghidra · error · LSHException

Could not drop index

Error message

Could not drop index: {}

What it means

Thrown in dropIndex when ResponseAdjustIndex response is null, i.e. the server rejected the AdjustVectorIndex (doRebuild=false) command. BulkSignatures surfaces the server's BSimError message as an LSHException 'Could not drop index: <message>'. A non-null but unsuccessful response (e.g. operation not supported) is handled as a logged error, not thrown.

Solutions

1. Read the message to learn the server's reason.
2. Confirm an index exists before dropping (rebuildIndex/dropIndex only make sense after population).
3. Retry on transient failures; report persistent unsupported/protocol errors.
4. Ensure privileges allow index operations.

Example fix

// before
bsim.dropIndex();  // no index / unsupported -> LSHException

// after
// only drop after the DB is populated and an index exists; otherwise skip

// only drop when an index is known to exist on a populated, supported DB

try {
    bsim.dropIndex();
} catch (LSHException e) {
    // message: "Could not drop index: <server>"; if unsupported or none exists, log and continue
}

When it happens

Trigger: Calling dropIndex on a database with no index to drop, a backend that does not support index operations, or during a connection/protocol failure that yields a null response.

Common situations: Dropping an index that was never built; backend (e.g. certain H2 configs) lacks vector-index support; transient server error; insufficient privileges.

Related errors

• Could not rebuild index
• Prewarm failed
• Could not change metadata
• Could not install new category
• Could not perform delete

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/b9b0d837157d86aa. Report an issue: GitHub.

Appendix: source

Thrown at Ghidra/Features/BSim/src/main/java/ghidra/features/bsim/query/ingest/BulkSignatures.java:600

		}
	}

	/**
	 * Drops the current BSim database index which can allow for faster signature ingest after
	 * which a {@link #rebuildIndex()} may be performed.  Dropping the index may also be done to
	 * obtain more accurate results albeit at the cost of performance.
	 * 
	 * @throws IOException if there's an error establishing the database connection
	 * @throws LSHException if there's an error issuing the query
	 */
	public void dropIndex() throws IOException, LSHException {
		DatabaseInformation info = establishQueryServerConnection(false);
		AdjustVectorIndex query = new AdjustVectorIndex();
		query.doRebuild = false;
		ResponseAdjustIndex response = query.execute(querydb);
		if (response == null) {
			BSimError lastError = querydb.getLastError();
			throw new LSHException("Could not drop index: " + lastError.message);
		}
		String dbDetail = "for database " + info.databasename + " (" + bsimServerInfo + ")";
		if (!response.success) {
			String msg = "Could not drop the index " + dbDetail;
			if (!response.operationSupported) {
				msg += ": operation not supported";
			}
			Msg.error(this, msg);
		}
		else {
			Msg.info(this, "Successfully dropped index " + dbDetail);
		}
	}

	/**
	 * Rebuilds the current BSim database index.
	 * 
	 * @throws IOException if there's an error establishing the database connection

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